Developing and validating measurement methods combining 6LiF sintered capsule and Mg2SiO4: Tb (TLD-MSO-S) for γ-ray dose evaluation at accelerator-based BNCT system

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2024-07, Vol.1064, Article 169443
• Main Authors: Suzuki, Shunsuke, Yagihashi, Takayuki, Nitta, Kazunori, Yamanaka, Masashi, Shimo, Takahiro, Sato, Naoki, Matsubayashi, Nishiki, Takata, Takushi, Sugimoto, Satoru, Hashimoto, Harumitsu, Shiba, Shintaro, Gotoh, Shinichi, Nagata, Hironori, Tanaka, Hiroki
• Format: Article
• Language: English
• Subjects: 6LiF; Boron neutron capture therapy; Quality assurance; Thermoluminescence dosimeter; γ-ray
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2024.169443

The radiation emitted from the beam aperture of the boron neutron capture therapy (BNCT) system includes not only neutrons with a wide energy range but also γ-ray, which is an undesirable dose for patients. Therefore, it is necessary to evaluate the γ-ray dose appropriately. Several methods have been proposed to evaluate the γ-ray dose in a neutron field. However, eliminating the influence of neutrons is challenging, and developing a more versatile and highly accurate measurement method is desired. We aimed to validate the γ-ray dose measurement method in a neutron field combining a commercial thermoluminescence dosimeter (TLD) named Mg2SiO4: Tb (TLD-MSO-S) and 6LiF sintered capsule for quality assurance. As a characteristic evaluation, the variation in sensitivity between TLD rods and dose linearity was determined using a medical linear accelerator. Furthermore, the perturbation and contribution of neutron dose were determined by Monte Carlo simulation, and measurements were performed at the accelerator-based BNCT system. We have found that γ-ray dose can be evaluated with an accuracy of and within ±7% between calculated and measured values and ±7% of reproducibility. •The method of γ-ray dose evaluation combining Mg2SiO4: Tb (TLD-MSO-S) and 6LiF sintered capsule in the neutron field was presented.•The factors used for γ-ray dose evaluation were determined by calibration using linear accelerator and MCNP calculations, and then verified in the neutron irradiation field.•The measured γ-ray dose can be evaluated with an accuracy of and within ±7% between calculation results and ±7% of reproducibility.